Appendix 3 - Summary of pressure (P) and temperature (T) conditions obtained with geothermobarometry. As Al2SiO5 is not present, some of the most used geothermobarometers of metapelites can’t be applied.	
 	 	 	 	 	 	
Sample	Method	Reference	P (Gpa)	T (°C)	Errors/conditions	
TC187	Plagioclase-Amphibole-Granet-Quartz*	Kohn & Spear (1990)	0.99	600°C	P±0.1GPa	
	Amphibole-Plagioclase*	Holland & Blundy, (1994)		605	with quartz	
				608	without quartz	
		Plyusnina, (1982)	0.80	540	P±0.1GPa T±60°C	
	Ti in amphibole	Otten, (1984)		661		
						
TC87	Amphibole-Plagioclase**	Holland & Blundy, (1994)		618	with quartz	
				619	without quartz	
		Plyusnina, (1982)	0.80	520	P±0.1GPa T±60°C	
	Ti in amphibole	Otten, (1984)		641		
						
TC88	Garnet-Biotite***	Thompson (1976)		631	T±80°C	
		Ferry & Spear (1978)		633	T±80°C	
		Hodges & Spear (1982)		688	T±60°C	
		Perchuk & Lavrent'eva (1983)	635	T±60°C	
		Indares & Martignole (1985)		656	T70°C	
		Perchuk (1991) A		618	quaternary-quarternary	
		Perchuk (1991) B		652	ternary-quaternary	
		Dasgupta et al. (1991)		661	T±60°C	
		Bhattacharya et al. (1992)		644	HW (1989)-Margules	
		Bhattacharya et al. (1992)		659	GS (1984)-Margules	
		Kleemann & Reinhardt (1994)	628	T±60°C	
		Kaneko & Miyano (2004-A)		663	With Fe3+ correction	
		Kaneko & Miyano (2004-B)		645	Without Fe3+ correction	
 	GBPQ***	Wu et al., (2004)	0.86	 	P±0.03, T = 660 	
						
* mean on 8 couples					
** mean on 9 couples					
*** mean on 7 couples/analyses					

References:
Bhattacharya, A., Mohanty, L., Maji, A., Sen, S. K. and Raith, M., 1992, Non-ideal mixing in the phlogopite–annite binary: constraints from experimental data on Mg–Fe partitioning and a reformulation of the biotite–garnet geothermometer: Contributions to Mineralogy and Petrology, v. 109, p. 107–111.
Dasgupta, S., Sengupta, P., Guha, D., and Fukuoka M., 1991, A refined garnet-biotite Fe-Mg exchange geothermometer, and its application in amphibolites, and granulites: Contributions to Mineralogy and Petrology, v. 109, p. 130–137.
Ferry, J.M., Spear, F.S., 1978, Experimental calibration of the partitioning of Fe and Mg between biotite and garnet: Contributions to Mineralogy and Petrology, v. 66, p. 113–117.
Hodges, K.V., and Spear, F.S., 1982, Geothermometry, barometry and the Al2SiO5 triple point at Mt. Moosilauke, New Hampshire: American Mineralogist, v. 67, p. 1118–1134.
Holland, T., and Blundy, J., 1994, Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry: Contribution to Mineralogy and Petrology, v. 116, p. 433–47.
Indares, A., and Martignole, J., 1985, Biotite – garnet geothermometry in the granulite facies: the influence of Ti and Al in biotite: American Mineralogist, v. 70, p. 272–278.
Khon, M.J., and Spear, F.S., 1990, Two new geobarometers for garnet amphibolites, with applications to southeastern Vermon: American Mineralogist, v. 75, p. 89-96.
Kaneko, K., and Miyano, T., 2004, Recalibration of Mutually Consistent Garnet- Biotite and Garnet Cordierite Geothermometers: Lithos, v. 73, p. 255–269.
Kleemann, U., and Reinhardt, J., 1994, Garnet-biotite thermometry revisited: The effect of A1VI and Ti in biotite: European Journal of Mineralogy, v. 6, p. 925–941.
Otten, M.T. 1984. The origin of brown hornblende in the Artfjallet gabbro and dolerites: Contribution to Mineralogy and Petrology, v. 86, p. 189–99.
Perchuk L.L., 1991, Derivation of thermodynamically consistent system of geothermometers and geobarometers for metamorphic and magmatic rocks, in Perchuk, L.L. ed., Progress in Metamorphic and Magmatic Petrology: Cambridge, Cambridge University Press, pp. 93–112.
Perchuk, L.L., and Lavrentieva, I.V., 1983, Experimental investigation of exchange equilibria in the system cordierite-garnet-biotite, in Saxena-Surendra, K., ed., Kinetics and equilibrium in mineral reactions: Advances in physical geochemistry, p. 199–239.
Plyusnina, L.P., 1982, Geothermometry and geobarometry of plagioclase–hornblende-bearing assemblages: Contributions to Mineralogy and Petrology, v. 80, p. 140–146.
Thompson, A.B., 1976, Mineral reactions in pelitic rocks II. Calculation of some P-T-X (Fe–Mg) phase reactions: American Journal of Science, v. 76, p. 425–454.
Wu, C.M., Zhang, J., and Ren, L.D., 2004, Empirical garnet – biotite – plagioclase – quartz (GBPQ) geobarometry in medium– to high–grade metapelites: Journal of Petrology, v. 45, p. 1907–1921.